Three tooth kinematic coupling

Abstract

A three tooth kinematic coupling based on having three theoretical line contacts formed by mating teeth rather than six theoretical point contacts. The geometry requires one coupling half to have curved teeth and the other coupling half to have flat teeth. Each coupling half has a relieved center portion which does not effect the kinematics, but in the limit as the face width approaches zero, three line contacts become six point contacts. As a result of having line contact, a three tooth coupling has greater load capacity and stiffness. The kinematic coupling has application for use in precision fixturing for tools or workpieces, and as a registration device for a work or tool changer or for optics in various products.

What is claimed is: 
     
       1. A kinematic coupling, consisting of; a pair of coupling halves having a bearing interface along three equally spaced lines of contact,   said three lines of contact extending along three equally spaced centerlines through a common centerline of said coupling halves.   each of said coupling halves having three equally spaced teeth,   said teeth of one of said coupling halves cooperating with spaces between said spaced teeth of another of said coupling halves, and   each of said three lines of contact pass along a surface on two of said three teeth.   
     
     
       2. The kinematic coupling of claim 1, wherein said teeth of one of said coupling halves have a curved surface. 
     
     
       3. The kinematic coupling of claim 1, wherein said teeth of the another of said coupling halves have a flat surface. 
     
     
       4. The kinematic coupling of claim 1, wherein each of said teeth of each of said coupling halves includes a tapered section on each side of each of said teeth. 
     
     
       5. The kinematic coupling of claim 4, wherein each of said teeth of each of said coupling halves includes a vertical section adjacent each of said tapered sections, said section being selected from the group of sections consisting of vertical, sloped, and curved. 
     
     
       6. The kinematic coupling of claim 1, wherein each of said coupling halves includes a relieved center portion. 
     
     
       7. In a kinematic coupling, the improvement comprising: said coupling consisting of a pair of coupling halves, each of said coupling halves being constructed to provide three equally spaced lines of contact,   each of said pair of coupling halves being provided with three equally spaced teeth,   said three lines of contact extending along three equally spaced centerlines of said coupling halves and   each of said three lines of contact passing along a surface on two of said three spaced teeth.   
     
     
       8. The improvement of claim 7, wherein said three teeth on one of said pair of coupling halves each has a curved surface, and wherein said three teeth on another of said pair of coupling halves each has a flat surface, and wherein said teeth of one of said pair of coupling halves are adapted to cooperate with teeth of another of said pair of coupling halves. 
     
     
       9. The improvement of claim 8, wherein each of said teeth include a pair of tapering sections. 
     
     
       10. The improvement of claim 9, wherein each of said coupling halves includes a relieved center portion. 
     
     
       11. The improvement of claim 10, wherein one of said coupling halves is constructed to include curved surfaces on the teeth, and wherein another of said coupling halves is constructed to include flat surfaces on the teeth. 
     
     
       12. The improvement of claim 11, wherein said coupling halves are constructed from material selected from the group consisting of hardened steel, cast iron, stainless steel, and structural ceramic. 
     
     
       13. The improvement of claim 12, wherein said coupling halves are each constructed of the same material. 
     
     
       14. The improvement of claim 12, wherein said coupling halves are each constructed of a different material. 
     
     
       15. The improvement of claim 12, wherein each coupling half is composed of a monolithic unit, wherein the fit between teeth depends on the straightness along the contacting surfaces.